1. Field of the Invention
The present invention relates to a tool pot used for a tool magazine of a machine tool, and more particularly, to a tool pot composed of a cylindrical synthetic resin portion over an entire length from an opening end to a tool gripping portion. The synthetic resin portion is made from thermo-plastic resin, and inner surface thereof is a tool attachment hole.
2. Description of the Related Art
In the prior art, Japanese Laid-Open Patent No. 2001-347434 discloses a tool pot composed of a cylindrical synthetic resin portion over an entire length from an opening end to a tool gripping portion. The synthetic resin portion is made from thermo-plastic resin, which is recyclable.
Inner surface of the synthetic resin portion serves as a tool attachment hole. A part of the inner surface of the attachment hole near an opening end is diverged toward the opening end and serves as a tapered supporting surface for holding tools.
The synthetic resin portion of the tool pot disclosed in above reference is injection molded from thermo-plastic resin material such as polyamide. The synthetic resin portion is provided on outer side thereof with reinforcing ribs for securing certain rigidity. If the ribs are thickened, rigidity of the synthetic resin portion is improved easily. However, thickening of the ribs may also cause mold shrinkage, and hinder the synthetic resin portion from attaining expected dimensional accuracy.
In order that the synthetic resin portion with reinforcing ribs secure rigidity and also avoid mold shrinkage, a great deal of effort has been made to design shape, size, or arrangement of the ribs. Consequently, there has not been so much freedom in design of the synthetic resin portion.
To improve rigidity while avoiding thickening of the ribs, it is conceivable to mix a great deal of reinforcing filler such as glass fiber into thermo-plastic resin material for the synthetic resin portion. If the thermo-plastic resin material itself is rigidified, however, inner surface of the tool attachment hole is rigidified, too, and may damage tools inserted into the hole if tools are dislocated from exact inserting position when inserted into the attachment hole. That is, hardening of the material itself cannot be an appropriate solution to the above problem.
In the synthetic resin portion of the tool pot, moreover, angle and inner diameter of the tapered supporting surface of the attachment hole, and length from the supporting surface to the tool gripping portion made of ball plungers or the like, which is located at the bottom of the tool attachment hole for gripping tools, requires dimensional accuracy.